Extraction turbine arrangement



Feb. 35, 1938. A. ROSCH ET AL 2,M,6M

EXTRACTION TURBINE ARRANGEMENT Filed D 2, 1956 Fig.

Their Attorn Patented Feb. 15, 1938 PATENT OFFICE EXTRACTION TURBINE ARRANGEMENT Arthur Bosch, Brieselang,

near Nauen, and

Herbert Neumann, Berlin-Wilmersdorf, Germany, assignors to General Electric Company, a corporation of New York Application December 2, 1936, Serial No. 113,920 In Germany January 23, 1936 4 Claims.

The present invention relates to extraction and mixed pressure turbine arrangements and more especially to a mechanism for controlling the flow of cooling water to the condenser for an extraction or mixed pressure turbine. The maintaining of constant flow of cooling water through the condenser leads to considerable waste and poor economy if the turbine is subject to considerable fluctuation in extraction fluid.

The object of our invention is to provide an improved construction and arrangement of mixed pressure turbine control whereby the efliciency, in particular the economy of the cooling water circulation, is substantially improved. This is accomplished in accordance with our invention by the provision of a control mechanism for the cooling water circulating pump, which mechanism controls the flow of cooling water through the condenser in response to changes in the amount of exhaust elastic fluid from the turbine. I

For a better understanding of what we believed to be novel and our invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing.

In the drawing, Fig. 1 illustrates a turbine arrangment embodying our invention and Fig. 2 shows a modification of a part of Fig. 1.

The arrangement of Fig. 1 comprises an ex-' traction turbine H) with an inlet valve H for controlling the flow of elastic fluid to the turbine and anexhaust conduit l2 for discharging exhaust fluid from the turbine. A conduit I 3 is connected to an intermediate point of the casing for extracting elastic fluid therefrom in which case the turbine operates as an extraction turbine or for conducting elastic fluid of a lower pressure than the inlet pressure to the turbine in which case the latter operates as a mixed pressure turbine.

An interstage valve I4 is provided for controlling the flow of elastic fluid from the extraction stage to the succeeding stage. Opening of the valve I4 causes an increased flow of elastic fluid from the extraction stage to the succeeding stage and consequently a decreased flow of elastic fluid through the extraction conduitl3. Vice-versa, closing of the interstage valve 14 increases the flow of elastic fluid from the extraction conduit l3 through the conduit l3, or from another viewpoint, increases the pressure in the extraction conduit l3. In the usual type of arrangement the pressure in'the conduit I3 is maintained constant. This means that during constant mechanical load output condition an increased flow of elastic fluid through the extraction conduit I3 causes a decrease in pressure in the lower stages, in particular in the stage behind the interstage- .valve I4 as regards the direction of flow of fluid through the turbine. The fluid exhausted from the turbine is discharged through the exhaust conduit l2 and condensed in a condenser l5, which latter includes a number of cooling tubes I6 through which cooling fluid such as water is circulated to efiect condensation of exhaust fluid from the turbine. The condensate is discharged from the condenser through a discharge conduit I'L The cooling medium such as water in the present instance is supplied to the condenser by means of a rotary pump [8 having an inlet conduit l9 connected to a suitable source of cooling medium, (not shown), and a discharge conduit l9a connected to a header 2!! of the condenser. The pump iii in the present instance is driven by an electric motor 2! operated at substantially constant speed. The pump i8 is provided with a bypass 22 having one end 23 connected to the discharge end lfia of the pump and another end 24 connected to the inlet IQ of the pump. This bypass serves to return a portion of the fluid discharged from the pump to the pump inlet. In order to utilize the energy of the fluid thus bypassed, the end 24 of the conduit 22 is preferably provided with a nozzle 25 disposed within the inlet of the pump. The amount of cooling medium thus by-passed is controlled by a valve 26 disposed withinthe conduit 22 and connected to automatic control means which in the present instance includes a difierential pressure responsive device having two bellows 2! and 28 connected to the right-hand end of a lever 29 having its left-hand end pivotally connected to the stem of valve 26 and an intermediate point supported on a fulcrum 30. The bellows 2! communicates through a pipe 3| with the extraction conduit l3 and the bellows 28 communicates through a pipe 32 with the turbine at a point past the interstage valve M. In the present instance the pipe 32 is connected to the turbine stage succeeding the extraction stage.

With this arrangement, an increasing flow of fluid through the extraction conduit I3 causes, due to the decreasing pressure behind the extraction valve, downward movement of the righthand end of the lever 29 which in turn effects opening movement of the bypass valve 26, thus causing an increase in the amount of bypassed cooling medium and consequently a decreasing flow of cooling medium to the condenser in accordance with the decrease of the amount of exhaust fluid from the turbine.

Whereas in the above example the flow of cooling medium to the condenser is controlled by means of a bypass to the pump, such flow may also be controlled by controlling the speed of the motor or prime mover for the pump. This is especially advantageous where the pump is driven by a turbine. An arrangement of this kind is shown in Fig. 2 in which a pump 35 for forcing cooling medium to a condenser is driven by an auxiliary turbine or prime mover 36 having a valve 31 for controlling the flow of operating fluid thereto. The valve 31 is pivotally connected to the left-hand end of a lever 38, which latter has a right-hand end supported on a fulcrum 39 and an intermediate point connected to a differential pressure-responsive device in the formof bellows 40 and 4!, corresponding to the bellows 28 and 21 respectivelyof Fig. 1. Other wise the arrangement is similar to that of Fig. 1.

During operation a decrease in pressure in the turbine stage succeeding the extraction valve causes collapsing of the bellows 40 and consequently downward movement of the left-hand.

end of the lever 38, resulting in closing movement of the valve 31. This reduces the flow of operating fluid to the auxiliary turbine or prime mover 36 and consequently reduces the speed of the pump 35 and the amount of cooling medium conveyed thereby.

Having described the method of operation of our invention, together with the apparatus which we now consider to represent the best embodiment thereof, we desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. Extraction and mixed pressure turbine arrangement including the combination of an elastic fluid turbine, a condenser for receiving exhaust fluid from the turbine, 'a conduit connected to an intermediate stage of the turbine, means including a pump for conducting cooling medium to the condenser, and means including a pressure-responsive device connected to the conduit and an adjustable bypass for the pump for automatically controlling the flow of cooling medium in responseto changes of the amount of elastic fluid flowing through the conduit.

2. Extraction and mixed pressure turbine arrangement including the combination of an elastic fluid turbine, a condenser for receiving exhaust fluid from the turbine, a conduit connected to an intermediate stage of the turbine, means for conducting cooling medium through the condenser comprising a pump, a motor for driving the pump, a bypass including a valve for the pump and means for automatically controlling the valve in response to changes of the pressure in the conduit and the pressure in the low pressure part of the turbine past said conduit.

3. Extraction and mixed pressure turbine arrangement including the combination of an elastic fluid turbine, a condenser for receiving elastic fluid exhausted from the turbine, a conduit connected to an intermediate stage of the turbine, means including a pump for forcing cooling medium into the condenser and means for automatically controlling the operation of the pump in response to changes in the amount of fluid exhausted from the turbine, said means including a device responsive to the difference in presrangement including the combination of a turbine, a condenser for receiving fluid exhausted from the turbine, a conduit connected to an intermediate stage of the turbine, valve means for controlling the flow of elastic fluid to the turbine, valve means for controlling the flow of elastic fluid from the intermediate stage to the succeeding stage, means including a pump and a motor driving the pump for forcing cooling medium into the condenser, a bypass for the pump, the bypass including a valve for controlling the flow of cooling medium therethrough and a discharge nozzle disposed within the inlet of the pump, and means for automatically controlling the last named valve comprising a diflerential pressure responsive device having one bellows communicating with the conduit and another bellows communicating with the succeeding stage.

ARTHUR ROSCH. HERBERT NEUMANN. 

